This invention relates to an ink supply device for an ink jet printer for drawing characters and figures on a sheet of paper or the like by causing ink particles to fly and controlling their trajectories.
There have been two types of ink supply devices for such an ink jet printer, one by which a pressure-applying means such as a pump is used to push the ink inside a tank to a nozzle and the other by which ink moves from a tank through a narrow passageway and is supplied to a nozzle at normal pressure by utilizing the capillary effect. When such a supply device is moved around, however, the ink inside the tank is shaken and foams are generated. Such foams are mixed with the ink and they travel together through the passageway to the nozzle. In the case of a printer equipped with a pressure-applying means such as a pump as described above, the foams can be forcibly pushed out of the nozzle. In the case of a printer relying on the capillary effect, however, small air particles grow larger as they accumulate inside the passageway over a long period of time, coming to prevent the flow of ink therethrough. Since the capillary effect is to be relied upon, the passageway for ink through the nozzle is extremely narrow and complicated in shape. If air particles accumulate inside such a passageway, the supply of ink may become insufficient for the purpose of printing.